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Biomedical subjects

D C Klein

Publications and source records attributed to D C Klein.

At least 217 records · Page 12Linked to original sources
PubMed1974

Arginine vasotocin: effects on development of reproductive organs.

Immature 25-day-old mice were injected daily with 1 microgram of arginine vasotocin for 3 or 4 days and killed 24 hours after the last injection. The ovaries were 30 percent smaller in treated females than in controls. The ventral prostates and accessory organs (seminal vesicles and coagulating glands) were less than half the size of these structures in control males. Similar results were observed when 15-day-old mice were given similar injections and killed 2 weeks after the last injection; furthermore, testis weights were 28 percent smaller than those of controls. It is speculated that arginine vasotocin, which has been found in mammalian pineal glands, might mediate effects of the pineal gland on normal sexual development.

Age Factors↗
PubMed1972

Rapid light-induced decrease in pineal serotonin N-acetyltransferase activity.

Light acting by way of the eye causes the dark-induced activity of serotonin N-acetyltransferase in the pineal gland of the rat to decrease with a halving time of about 3 minutes. This effect, which is one of the more rapid physiological changes known to occur in the activity of any enzyme that metabolizes biogenic amines, appears to explain the rapid increase in the concentration of pineal serotonin that is caused by light exposure at night.

Acyltransferases↗
PubMed1971

Melatonin metabolism: neural regulation of pineal serotonin: acetyl coenzyme A N-acetyltransferase activity.

There is a diurnal rhythm in the activity of serotonin N-acetyltransferase in the rat pineal gland. In the normal rat, the nocturnal enzyme activities are 15-to 30-fold greater than are daytime activities. This rhythm is abolished by decentralization or removal of the superior cervical ganglia, procedures that interrupt the only source of central neural input to the pineal gland. This effect of superior cervical sympathectomy on the N-acetyltransferase rhythm cannot be attributed to changes occurring in the denervated pineal parenchymal cells. When chronically denervated glands are placed in organ culture with norepinephrine, the neurotransmitter normally located in sympathetic terminals in the gland, N-acetyltransferase activity increases 10- to 20-fold. These data indicate that superior cervical sympathectomy abolishes the N-acetyltransferase rhythm by elimination of the input of central signals to the gland. These signals appear to regulate the N-acetyltransferase rhythm in the normal rat by regulation of the release of norepinephrine from the sympathetic terminals within the pineal gland.

Acyltransferases↗